1. Field of the Description
The present description relates to magnetic tape data storage and, in particular, to methods and systems for accessing data segments or files (or blocks) on a magnetic tape (or, more simply, “tape”) in a more time efficient manner.
2. Relevant Background
For decades, magnetic tape data storage has offered cost and storage density advantages over many other data storage technologies including disk storage. A typical medium to large-sized data center will deploy both tape and disk storage to complement each other and with the tape storage often used for backup and archival data storage. Due to the increased need for securely storing data for long periods of time and due to the low cost of tape, it is likely that tape-based data storage will continue to be utilized and its use will only expand for the foreseeable future.
Briefly, magnetic tape data storage uses digital recording on to magnetic tape to store digital information, and the tape is packaged in cartridges and cassettes (i.e., the storage media or simply “media”). The device that performs writing and reading of data is a tape drive, and tape drives are often installed within robotic tape libraries, which may be quite large and hold thousands of cartridges to provide a tremendous amount of data storage (e.g., each tape may hold several terabytes of uncompressed data).
Presently, tape data have been accessed in the order that the data was written upon the tape, which is typically random with each file being at spaced apart locations on the tape. For example, a host may read a set of files on a tape, such as a set of files used to archive a particular set of data, via a tape drive containing that tape. The host would read the set of files in the order that they were written which may be very inefficient as the files may be located in numerous different locations that may be in different wraps, in different servo bands, and on an opposite side of the tape centerline (or in a different head travel direction). This inefficiency has been tolerated in the past, but the access time has been increasing as tapes have been more and more densely written with increasing numbers of wraps and overall tape length.
Hence, there remains a need for improved methods (e.g., software programs or applications) for use in determining better ways to access data files or blocks on a tape. Preferably, such methods would be useful with existing and yet to be developed hosts, tape drives, tapes/media, and other components of a tape-based data storage system.